sputter, bacfire and cut off!

[blackdogg6164]


Jul 29 at 10:58 AM





I have a 2008 pitbull that is having some sort of performance issues starting last Saturday. on the parkway in Pittsburgh, I was at a decent rate of speed and the bike began to surge and cut off. I restarted while coasting and my pit sputtered, backfired, and cut off again. it takes 5 or 6 pushes on the start button (usually 2) to get it to turn over again and initially when it turns over, it runs ok, then sputters, backfires and dies. after pulling over with my buddies I had to call for a trailer and get it home. the next day, I changed the plugs and still the sputtering, backfiring and cutoff. do not know what to do. I filled up the tank, it ran as usual for about 2-3 hrs and then the RPMs dropped on the parkway. I got it started while still coasting but the tach would not go past 2000 RPMs and pow (backfire) and cutoff. any ideas? new plugs so that is out. going to check the fuses next (I'm hoping they are under the seat) and then some serious praying. I always use 93 octane. any and all help or info will be helpful and greatly appreciated.

 

[heybaylor]

check your fuel tank vent, sounds like a vacuum lock , not letting air in =no gas out.
btw , welcome to the forum

 

[B RADDD]

i had a similar problem,turned out to be my gas cap was bad.the vent holes were clooged making it vapor lock.loosen your cap and run it .it might be your problem.

 

[05chop]

Carburated? all of your problems could be fuel related or electrical related my first check would be check for fuel flow (engine off)out of the petcock.then get out your muti meter check key switch then check volts at battery (running) then check resistance of coil (engine off) check volts going to coil (engine off key on) check plug wire resistance.Also could be ignition modual (heat it up with hair dryer engine running)see if it drops out or starts cutting out.If its carburated could be a plugged jet in carb.Most important check voltage drop while starting engine could be bad connection or bad battery.All of these checks should get you an answer your looking for just take time and searching on BDB FORUM.

 

[BigDogBro1]

EFI or Carb?

Check all wire connections and crimps very carefully for clean surfaces and tightness.
If EFI it could be MANY ELECTRICAL contact points.
Fuel pump pressure-
Key switch contacts-
EHC harness connections-
Headlight bucket bulb connection melted and shorting out.
Other various electrical connections-

Start with the easy stuff and eliminate them.

 

[Iman]

Check for proper venting of gas cap first then go from there

 

[Dragonslave]

Check for proper venting of gas cap first then go from there

Agreed....Check to run with the gas cap off before you try anything else. Had the same problem myself until I installed a vent hose.

 

[BadDawg Bill]

Agreed....Check to run with the gas cap off before you try anything else. Had the same problem myself until I installed a vent hose.

Yep X2. Next I'd check the coil. When it heats up it could go bad.

 

[blackdogg6164]

I tried it with the cap off. I pulled the seat and checked the only fuse I could find.....not blown. my horn was loose, it was a mother to tighten but I thought the ground was loose and may have caused some intermittent shortage. changed the plugs. does anyone have any pics as to where the coil is located? when I purchased the bike from Bair's (North Canton, OH), the previous owner did not have the manual with the bike. one other question: what the heck are those wires which run in to the cylinder heads? just wanted to thank you all with your help.....me and a buddy thought about looking for a fuse box but could not find one of those either. I'm guessing I have an electrical issue because of the tach gauge not going past 1K (it was accurate because the motor speed seemed locked at that RPM as well...electrical issues are the worst.

 

[francoblay1]

Coil, left side between cylinders... where you stick the key in (follow the spark plug wires).

Wires into cylinders = Compression Release

Need a Manual? PM me your email address.

 

[BadDawg Bill]

Ya, I'd say it's a bad coil. Had that happen to me a few times. Look for some orange or brown goop leaking from the coil. It could also be a bad wire connection.

 

[Sven]

I'm with 05Chop. I want to make sure I'm putting out a charging system so I can work the diodes and resistors at 5v. I'm going assume this is a computer bike with a box of 1's and 0'shit! Does that have a cam or crank sensor?

I turn a page of Chop Hers so it vibrates, shes so happy but the bike runs like shit. Wait a minute, she first starts out cold and I get her all warm and then before you know it, that heat on her sensor make sense?

Then, I turn the page and see an ohm meter set to 20v and I really start to get a hardon. WATT is this I say? I say a tach signal and a cam sweep is a crank signal and eat that sweep of the magnetic field.

So mechanically speaking, she may be in heat and her you know has this huge puss filled with it burns when you pee kind of heat?

:roll:

OR...

 

[BBChopper]

I'm with 05Chop. I want to make sure I'm putting out a charging system so I can work the diodes and resistors at 5v. I'm going assume this is a computer bike with a box of 1's and 0'shit! Does that have a cam or crank sensor?

I turn a page of Chop Hers so it vibrates, shes so happy but the bike runs like shit. Wait a minute, she first starts out cold and I get her all warm and then before you know it, that heat on her sensor make sense?

Then, I turn the page and see an ohm meter set to 20v and I really start to get a hardon. WATT is this I say? I say a tach signal and a cam sweep is a crank signal and eat that sweep of the magnetic field.

So mechanically speaking, she may be in heat and her you know has this huge puss filled with it burns when you pee kind of heat?

:roll:

OR...

jestem z 05 Odcinają. potrzebuję (chcieć) żeby upewniać się usuwam system oskarżenia tak (więc) mogę pracować diody i *resistors* przy *5v*. JA jestem chodzenie przyjmują (przypuszczać) to jest komputerem *bike* z skrzynką (kabina) 1-ego i *0'shit*! Robi który ma *cam* albo *crank* *sensor*? obracam stronę Odcinają Jej tak (więc) to *vibrates*, *shes* tak (więc) szczęśliwy ale *bike* biegnie (przesuwa się; działanie) lubią *shit*. Czekają minuta, ona pierwszy (najpierw) starty (początki) poza chłód (chłodny) i otrzymuję (dostawać; rozumieć) jej cały ciepły i potem zanim wy poznajecie to, co (żeby; który) nagrzewają na jej *sensor* mają sens? Potem, obracam stronę i widzą miernik omu umieszczają *20v* i JA rzeczywiście rozpoczynać (początek; start) otrzymywać (dostawać; rozumieć) *hardon*. *WATT* jest to (to) mówię (przemawiać)? mówię (przemawiać) *tach* sygnał (sygnalizować) i *cam* obejmować (mknąć; objęcie; rozpiętość) jest *crank* sygnał i jedzą co (żeby; który) obejmować (mknąć; objęcie; rozpiętość) *magnetic* teren (polowy). Tak (więc) mechanicznie mówiący (rozmowa; mówiący), ona może jest w upale i jej wy poznajecie ma ten (to) ogromny *puss* zapełniany tym pali się (wypala) kiedy wy *pee* widok upału?

 

[Sven]

jestemoment, 05 praco the diody & *resistors* for integrity

to jest put *bike*z *cam* a *crank* *sensor* into question.

*vibrates*, *shes* cutting out.

bike* starty uppy all poza chłód wać;

nagrzewają na *sensor* mają sens?

Potem, *20v* (początek; start) testing.

*WATT* jest to is know your basics or it makes no sen (to) mówię.

i *cam* cum up wit a jest of a *crank* sygnał i jedzą don't know it's shot, no?

jest w upale i jej wy poznajecie tech and ma ten (to).

Are we clear? no matter how you *pee* widok upału?

 

[Sven]

I filled up the tank, it ran as usual for about 2-3 hrs and then the RPMs dropped on the parkway.

Please take no offense to topping off the gas tank and riding for 3 hours it's the gas cap.


BBChopper, I am not taking away any diagnostic post from anyone, no way, but not this time, read the OP. Think how frustrated the OP is. It's not my bike, but it sure is disturbing how one concludes his situation is the same as his? You know the OP is just as lost so you sort of make him go thru steps for nothing.

Compression = It starts so it's not compression.
Fuel = For 3 hours it's not fuel.
Spark = A computer bike lives or dies by a cam or crank sensor. I think this might be spark related, not fuel. So yes at this time a coil is a possibility.

Please take no offense to this, but apologies to the gas cap. :roll:

 

[francoblay1]

:roll::roll::roll: I did translate it and it´s Polish!!!! :roll::roll::roll:

I had a good laugh!

 

[blackdogg6164]

thanks Sven. I tend to agree because even a sputtering bike will have some variance in the tach readings up or down. this pit locks steady on 1000rpms. any turn on the throttle and no change. right before it cuts off and POW! all the tach lights around the gauge flash. now it may take 5 or 6 pushes on the run button before it will start. when I first bought it took two. is a coil failure a relatively common thing? crank sensor?

 

[Mikeinjersey]

Just a thought. A stuck float in a carb could give similar symptoms from flooding.

 

[Sven]

is a coil failure a relatively common thing? crank sensor?

Electrically, yes. Spark is: CS/Coil/Trigger Box.

Crank sensor = Heat sensitive. Comes and goes.
Coil = Once on the blink, it's throughout the range I would assume.
Spark box = This guy is more the unit I'm thinking of. Sort of start the bike and pull these wires coming out of the box [to wherever they go] and does the bike stall and lose spark?


Mikein,

Float sending in more fuel as in stuck, correct? = Over rich starting. Plug fouling.
Float is stuck and say he walks away from the petcock and it's left open = Lots of lost gas and into the crankcase, pumped back into the oil bag and fill that puppy with gas. The smell of gas when upright and the float is now filling the air cleaner and, do this: plug the sink and watch how it settles all even across the kitchen top = No mention of a smell of gas. No mention of losing gas and the breather is up at the air cleaner say dumping in that vapor smell of a rich, stuck float. Still no complaint of a smell, nor poor gas mileage. That's just my hunch about your hunch and how my hunch turns that into, no offense to the casing but, sausage. :up:

 

[blackdogg6164]

I am finally going to pull the coil cover and give the coil a once over. any instruction on how to proceed once I have it exposed? anything to look for?